The present invention relates to a three dimensional linear machining apparatus for three dimensional machining on a long-shaped member, such as a pipe, such as a laser beam machine, a plasma cutting machine, and a gas cutting machine.
Such kind of conventional three dimensional linear machine which has been proposed is the three dimensional laser beam machine wherein the direction of a torch from which laser beam is radiated is three-dimensionally adjustable with respect to a workpiece. Such a three-dimensional laser beam machine can three-dimensionally machine a workpiece by a linear/arc interpolation instruction for moving and driving a torch on a straight line/an arc or a cylindrical interpolation instruction for rotating a workpiece. In case where the sectional shape of a workpiece to be machined is an irregular shape having a corner, but the feed speed of the torch with respect to the workpiece can not be uniformly maintained in a machining path passing through the corner since the linear/arc interpolation instruction and the cylindrical interpolation instruction can not be simultaneously controlled, so that irregularity may be formed on a surface cut by machining. That is, it is difficult to maintain a cut surface having no irregurality and to successively machine a member having an irregular shape along the above-mentioned machining path. For these reasons, the member having the irregular shape is necessary to be machined every each machining face of the workiece, so that much labor and/or long time is required for such operation, and it is difficult to actualize speedy machining.
Under such a situation, such a method is known that the machining path passing through a corner is successively machined concerning a workpiece, such as an irregularly shaped member, by using the interpolation instruction of micro line segment by the machining program produced by a CAD/CAM unit.
But, long time is necessary for complex computation in such a machining, and besides, specific skill is also necessary. In addition, a CAD/CAM unit is separately necessary, and it is necessary to prepare enormous memory capacity for a machining program produced. Besides, the interpolation instruction of micro line segment is used, so that the machining speed is slow and it is difficult to actualize speedy machining.
Therefore, the development of the three dimensional linear machining apparatus for easily executing a machining without a skill wherein the face cut by machining can be maintained in a good condition, having no irregularity, speedy machining can be actualized by a successive machining on a workpiece, such as an irregularly shaped member, and a CAD/CAM unit and the memory capacity for a machining program are not necessary has been desired.